A police corruption trial that detailed widespread drug dealing between officers in an elite crime squad and leading figures in the underworld ended yesterday with three disgraced detectives being jailed.

Det Con Thomas Kingston, 42, Det Con Thomas Reynolds, 40, and Det Sgt Terance O'Connell, 43, all members of 9 regional crime squad based at East Dulwich, south London, should have been at the forefront of the fight against drugs crime. Instead, they called themselves "the groovy gang" and for five years were part of a conspiracy to recycle drugs they seized in raids for their own profit, the Old Bailey heard.

Kingston and Reynolds were jailed for three and a half years each after they were convicted of conspiracy to supply £7,500 of amphetamine sulphate.

O'Connell was jailed for two years for perverting the course of justice by trying to cover up for his two colleagues. He was cleared of conspiracy to supply.

Two other members of the squad, Robert Clark and Christopher Drury, were jailed in February for their involvement in the scam, but their convictions could not be published before the end of the trial for legal reasons. Clark, the ringleader of the group, was sentenced to 12 years. Drury received 11 years.

Evidence presented at the two trials showed the detectives were involved in lucrative double-dealing.

Their corrupt activities were exposed when a drug dealer, Evelyn Fleckney, who was having an affair with Clark, turned supergrass, and another officer in the squad, Det Con Neil Putnam, gave evidence against his colleagues after "wrestling with his conscience", the court heard.

Fleckney, a powerful drug baroness, described how she became a police informer in the early 1990s. She and Clark became lovers, staying in £200-a-night hotels - signing in under the name Bart Simpson - going on holidays to the Canary Islands and exchanging expensive gifts.

They even attended police functions together.

However, their relationship was also a business one.

Fleckney, who was known as "the chairman of the board", fed Clark information on major drugs shipments. Part of any drugs seized by the squad were stolen by Clark and recycled by Fleckney through her network of dealers. The profits were shared among the detectives involved.

Orlando Pownall, who prosecuted in both trials, said: "This had the effect of returning to the streets the very drugs that Clark was entrusted to seize. Those from whom they 'stole' could hardly be described as victims and would be unlikely to complain on arrest."

The corrupt activities were in full swing in September 1991 when Putnam joined the squad. That month Fleckney told Clark a large quantity of cannabis resin was being dropped from a light aircraft over the village of Nutting in East Sussex.

Putnam was present as officers from the squad seized the drugs and made arrests. A few days later, Clark handed Putnam £300, the first of several payments.

"He knew it was a corrupt payment, but did not realise precisely what it was for," said Mr Pownall.

In the second trial, Putnam described how the police were tipped off that a quantity of amphetamine was being delivered to an address in Clapham, south-west London, in July 1995.

Kingston and O'Connell were among officers who went to the scene. They took two of the six packets they found and put them in a carrier bag.

Putnam, who was there as an exhibits officer, was asked by Kingston to take the bag to Reynolds, who was off duty.

"Reynolds arranged for the drugs to be sold and a few weeks later gave Putnam £500, his share of the proceeds," said Mr Pownall.

Sentencing Kingston and Reynolds yesterday, Judge David Paget QC said: "You have been convicted of what is a very grave offence."

Suspicions about the squad and rumours of the relationship between Fleckney and Clark persisted throughout the 1990s, but nothing could be proved.

However, Fleckney turned supergrass after she was convicted in March 1998 of conspiracy to supply ecstasy, cocaine and cannabis and jailed for 15 years.

At the time of her arrest, she was controlling a multimillion international drugs distribution network.

She boasted: "There are not many dealers like me. I could have a million pills if I wanted. I could have had 100,000 delivered yesterday."

Putnam, who was described as a devout Christian, was then questioned by Scotland Yard's complaints investigation bureau and decided to give evidence against his colleagues. Both he and Fleckney pleaded guilty to a number of drug-related offences in November last year.

Putnam was jailed in February for three years 11 months, but is now free.

Fleckney was sentenced to four and a half years for her involvement with the detectives. The sentence runs concurrently with her 15-year term.

The Old Bailey heard that the officers in the squad "became a rule unto themselves", Mr Pownall said.

"There was no supervision and through the lack of supervision there grew a sense of arrogance, a feeling that they were untouchable."

The judge in the first trial, Mr Justice Blofeld, condemned the lack of supervision from senior officers, although he praised CIB for its investigation.